![](bg6.png)
This constraint makes a service provider more scalable
because the provider does not have to store state
information between requests. This is effectively
"service in mass production" since each request can be
treated as generic. It is also claimed that this constraint
improves visibility because any monitoring software
can inspect one single request and figure out its
intention. There are no intermediate states to worry
about, so recovery from partial failure is also relatively
easy. This makes a service more reliable.
Taking into account these main particularities of
SOA, we can consider the main challenges for our
Discovery-Orchestrate-Deliver concept in a Semantic
Service-Oriented Architecture (SSOA) are the
descriptions of messages and services, the
management of services and the process for facilitating
the access to services.
At "Discover" level, the semantic descriptions of
services – as they are made from the external
descriptions of messages found in WSDL – make
more easy the classification of services in the service
repository, because these descriptions are structured
upon a taxonomy of the concepts manipulated by the
services. This taxonomy facilitates the logical ordering
of services by domains, subdomains, topics and
subtopics, and consequently facilitates their
management. These semantic descriptions, as they can
match with the service requirements contained in the
user's original request, are also a good means to make
more easy the discovery of corresponding services.
At "Orchestrate" level, the "composition handlers"
contained in the semantic descriptions of services are a
good enabler for an automatic orchestration process
able to aggregate several convenient services.
The semantic descriptions of a new service, and
mainly their taxonomic abilities, are still used at
"Deliver" level, when the Discover-Orchestrate-
Deliver mechanism has to store them as logically as
possible and to insert them in the existing structure of
the semantic repository.
7 CONCLUSION
Within a wide-communicating world where services
become more and more sophisticated and are on the
beginning to expose their semantic dimension, we
consider it is important to propose solutions in which
anybody could be able to create his own services in
some simple clicks. This paper reveals one of the
reflexion axis we currently have in this direction, and
we hope we could convince the reader that a semantic
approach, through the use of semantic descriptions of
services, helps in an important way the mechanisms
for building, holding and processing any kind of Web
service.
Moreover, we tried to show how Semantic SOA-
based mechanisms, if possible leant on IMS
development platforms, can provide high-value
capabilities for new generation service creation and
delivery: a simpler way to express a service, a faster
way to get and use it, a cheaper solution for the end-
user because it is simpler and faster.
We are convinced that IMS services are the good
base to develop such kind of rich services and use
interaction, including dynamic search, discovery and
publishing of web information associated to a multi-
media call session, and we think semantic Web
services are the good means to do it.
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